Trinadtsatiletnyuyu Meri Mari Anderson vospityvayut razvedennye roditeli, poetomu po resheniyu suda ona vynuzhdena shest mesyatsev zhit u ottsa, a ostavshiesya polgoda - u mamy. Podstraivayas pod roditeley, devushka kazhdyy raz stanovitsya drugoy versiey sebya: v Andersonvile eto tihaya i nezametnaya Meri, a v Bostone - veselaya i boykaya Mari.
Na stranitsah svoego dnevnika (na samom dele eto buduschiy roman o lyubvi!) devushka rasskazyvaet o tom, kak ona prozhivaet dve raznye zhizni, delitsya svoimi perezhivaniyami i zadaetsya voprosom: kto zhe ona na samom dele - Meri ili Mari?
